Michael Ashley is part of a team observing the effects of small objects in the Kuiper Belt region of the solar system. These objects are between 300m and 1km in size and can't be seen with a telescope, or even a space telescope. These observations may affect ideas about how the solar system originally evolved in the very early stages.

http://www.abc.net.au/rn/scienceshow/stories/2006/1712664.htm#

To quote:

Robyn Williams: Lots of lots of rocks floating around there.

Michael Ashley: Yes.

Robyn Williams: How many? Thousands?

Michael Ashley: No, many more than that. It's very hard to say. There have been a thousand or so discoveries of large ones over several hundred kilometres in size but we think there could be 10 to the 11th power or more rocks going down to very small sizes.

Robyn Williams: That's a huge number.

Michael Ashley: It's an incredible number.